Effect of Irigation Efficiencies on Nitrogen Leaching Losses

Abstract

The literature was reviewed to determine the effect increasing irrigation efficiencies have had on NO3-N leaching. The mass of NO3-N leached is directly related to the drainage volume. By increasing irrigation efficiencies, both the drainage volume and amount of NO3-N leaching are reduced. Both water management and nitrogen management are important in controlling NO3-N leaching. By using improved water management practices that control the amount of water applied and using the proper time to apply water, the irrigation efficiency is increased and NO3-N leaching is reduced. Applying only enough N fertilizer to meet crop requirements for a realistic yield goal, time of application and use of slow release fertilizers are N management practices that will reduce NO3-N leaching. However, it is impossible to reduce NO3-N leaching to zero in the humid region on coarse‐textured soils and still maintain adequate crop yields. Nitrogen simulation models cannot be widely used to evaluate N management practices and irrigation water management practices that increase irrigation efficiencies because of the lack of required input data.